Online lectures might be able to scale, but communication platforms and social networks cannot.

I would say more than half of what you learn is from your peers. People who by design were already filtered to be at a high baseline of competence and are forced to go through the same curriculum in the same timeframe as you.

No professor or expert can explain a concept better than someone similar to yourself who recently figured it out. There's also an immense amount of camaraderie built from helping each other grow. All of this is lost when you're just one of millions watching a video where most of the public discussion is dumb.

A little artificial exclusivity isn't a bad thing.